The invention relates to razor blade assemblies for mounting on handles via pivotal connections.
A well-known razor blade assembly, e.g., as shown in U.S. Pat. Nos. 4,573,266 and 4,586,255, employs a spring-biased guard member at the front of the assembly, a lubricating-strip cap potion at the back, and two spring-biased blade members between them. U.S. Pat. No. 5,249,361 shows a similar razor blade assembly with a fixed-guard. Both versions of the assembly have rails and circular surfaces for making pivotal connections with shell bearings on razor handles. Spring-biased cam followers on the razor handles interact with cam surfaces on the bottoms of the razor blade assemblies so as to bias the assemblies to neutral positions relative to the handles. During shaving, the assembly can pivot forward (clockwise) or backward (counterclockwise) from the neutral position relative to the handle, and the blades can move within the housing relative to the skin surface in order to follow the contours of the skin surface during shaving. In commercial embodiments of these razor blade assemblies (available under the Sensor and Sensor Excel trade designations from The Gillette Company), the shell bearings provide pivoting about an axis located between and above the two resiliently moving blades (considering their unloaded state as a reference). In particular, the pivot axis is located at the center of the slot in which the primary (forewardmost) blade supporting member is disposed and at the top of a clip that retains the blade members to the cartridge housing. Thus, the pivot axis is provided above the cutting edges of the blades and above the housing. This pivot axis location may therefore be referred to as being located "in the face" (that is, above the skin-engaging members) during shaving of a face. The razor blade assemblies are discarded after a number of shaves, and replacement razor blade assemblies are used with the handles containing the shell bearings and the spring-biased cam followers. The same razor handle can be used with both versions of the razor blade assembly, because they both have the same size rails and circular surfaces.